Aqueous polyvinylidene fluoride composition

Abstract

The invention relates to a separator for non-aqueous-type electrochemical device that has been coated with an aqueous fluoropolymer coating. The fluoropolymer is preferably polyvinylidene fluoride (PVDF), and more preferably a copolymer of polyvinylidene fluoride. The fluoropolymer coating provides a porous coating on porous substrate separator used in non-aqueous-type electrochemical devices, such as batteries and electric double layer capacitors. The fluoropolymer coating improves the thermal resistance and mechanical integrity, and lowers the interfacial electrical impedance of the porous separator. The fluoropolymer composition optionally contains powdery particles that are held together on the separator by the fluoropolymer binder. In one embodiment, the starting fluoropolymer dispersion is free of fluorinated surfactant. In another embodiment, one or more fugitive adhesion promoters are added.

Dependencies are inferred from the claim text.